Bootstrap snippet and html example. bs4 sign in

<div class="container h-100">
    		<div class="row h-100">
				<div class="col-sm-10 col-md-8 col-lg-6 mx-auto d-table h-100">
					<div class="d-table-cell align-middle">

						<div class="text-center mt-4">
							<h1 class="h2">Welcome back, Dey</h1>
							<p class="lead">
								Sign in to your account to continue
							</p>
						</div>

						<div class="card">
							<div class="card-body">
								<div class="m-sm-4">
									<div class="text-center">
										<img src="https://bootdey.com/img/Content/avatar/avatar6.png" alt="Andrew Jones" class="img-fluid rounded-circle" width="132" height="132">
									</div>
									<form>
										<div class="form-group">
											<label>Email</label>
											<input class="form-control form-control-lg" type="email" name="email" placeholder="Enter your email">
										</div>
										<div class="form-group">
											<label>Password</label>
											<input class="form-control form-control-lg" type="password" name="password" placeholder="Enter your password">
											<small>
            <a href="pages-reset-password.html">Forgot password?</a>
          </small>
										</div>
										<div>
											<div class="custom-control custom-checkbox align-items-center">
												<input type="checkbox" class="custom-control-input" value="remember-me" name="remember-me" checked="">
												<label class="custom-control-label text-small">Remember me next time</label>
											</div>
										</div>
										<div class="text-center mt-3">
											<a href="index.html" class="btn btn-lg btn-primary">Sign in</a>
											<!-- <button type="submit" class="btn btn-lg btn-primary">Sign in</button> -->
										</div>
									</form>
								</div>
							</div>
						</div>

					</div>
				</div>
			</div>
		</div>

body{
    background-color: #DCDCDC;
    margin-top:20px;
}
.card {
    margin-bottom: 1.5rem;
    box-shadow: 0 1px 15px 1px rgba(52,40,104,.08);
}

.card {
    position: relative;
    display: -ms-flexbox;
    display: flex;
    -ms-flex-direction: column;
    flex-direction: column;
    min-width: 0;
    word-wrap: break-word;
    background-color: #fff;
    background-clip: border-box;
    border: 1px solid #e5e9f2;
    border-radius: .2rem;
}